Our invention relates to apparatus for feeding a bar or rod, or a plurality of bars or rods at one time, to and away from a processing station therefor such as a bending station where the bar or bars are bent into desired shape. More specifically, our invention is directed to such apparatus capable of feeding successive required lengths of a desired number of bars, such as reinforcing steel bars, in a vertical pile through a bending or like processing station. Hereinafter in this specification and in the claims attached thereto, we will use the word "bar" to denote any elongate material that can be handled by the apparatus of our invention.
A variety of bar feed or transfer apparatus have heretofore been suggested and used in conjunction with bending machines. Examples are found in Japanese Laid Open Utility Model Application No. 57-52217 and Japanese Laid Open Patent Application No. 56-91936. These prior art devices are unsatisfactory in that their longitudinal dimensions are greater than the lengths of bars to be fed thereby. The greater the lenth of bars to be handled, the more is the longitudinal dimension of the apparatus. Thus, by reasons of the floor space required and the manufacturing costs, the prior art apparatus has generally been restricted to use with relatively short bars.
We are also aware conventional apparatus employing pairs of rolls for frictionally feeding bars. The use of feed rolls is objectionable, however, because of errors in feeding lengths due to unavoidable slip.
An additional problem with the prior art arises in conjunction with the simultaneous bending or like processing of a plurality of bars. If their diameter allows, bars should of course be processed in groups of two or more, rather than one by one, for higher production. Heretofore, each group of bars has either been previously fastened together into raftlike form or been fed in a vertical pile between pairs of upstanding guides. The fastening together of successive groups of bars is undesirable because of the separate fastening means required. The provision of the guides for transporting bars in a vertical pile is preferable. As conventionally constructed and arranged, however, the guides have imposed limitations upon the bending or like processing of the bars because of their interference with the movable parts of the feed apparatus or of the bending or like processing mechanism.